Electrical machine brush and method and apparatus for manufacturing the same

ABSTRACT

A brush for electrical machines is manufactured in a manner that one end of a conductor wire is embedded in the top surface of the brush and is molded-in perpendicular to the direction of compression of the brush. The brush assembly is automatically manufactured by the following steps: feeding a powdered material for the brush into the compression chamber while inserting a conductor wire into the powdered material compressing together the powdered material and the conductor wire in a direction perpendicular to the conductor wire, cutting the conductor wire apart and knocking out a compressed article from the compression chamber.

Elite States atent [1 1 Ohta [ 1 Sept. 23, 1975 1 ELECTRICAL MACHINE BRUSH AND METHOD AND APPARATUS FOR MANUFACTURING THE SAME [75] Inventor: Kizo Ohta, Nishinomiya, Japan Related U.S. Application Data [62] Division of Ser. No. 338.770, March 7, 1973,

abandoned.

[56] References Cited UNlTED STATES PATENTS 10/1919 Becker 29/630 E 4/1929 Sherwood 29/630 E 9/1929 Hall H 425/125 1.831.144 11/1931 Shearer 425/125 3.416191 12/1968 Richter et a1.. 425/411 3,712.781 1/1973 Schmier 425/411 Primary ExaminerC. W. Lanham Assistant Examiner-James R. Duzan Attorney. Agent, or FirmArmstrong, Nikaido & Wegner [57] ABSTRACT A brush for electrical machines is manufactured in a manner that one end of a conductor wire is embedded in the top surface of the brush and is molded-in perpendicular to the direction of compression of the brush. The brush assembly is automatically manufactured by the following steps: feeding a powdered material for the brush into the compression chamber while inserting a conductor wire into the powdered material compressing together the powdered material and the conductor wire in a direction perpendicular tc the conductor wire, cutting the conductor wire apart and knocking out a compressed article from the compression chamber.

1 Claim, 6 Drawing Figures US Patent Sept. 23,1975 Sheet 1 of3 3,906,624

FIG.

US Patent Sept. 23,1975 Sheet 3 Of3 3,906,624

ELECTRICAL MACHINE BRUSH AND METHOD AND APPARATUS FOR MANUFACTURING THE SAME This is a division of application Ser. No. 338,770, filed Mar. 7, 1973, now abandoned.

This invention relates to a brush for use as a current collector in electrical device such an electric motor, 7

and a method and apparatus for manufacturing the same.

conventionally, electrical machine brushes have been prepared by compressing a powdered material filled within a die, baking or sintcring the resultant compressed mass to form a brush and embedding one end of a conductor wire (i.e. brush shunt or flexible) into a bored hole of the carbon brush, using conventional methods such as riveted connection, tamped connection, etc. Such a manual operation is very cumbersome and inefficient, and furthermore it is difficult to maintain constant an electrical resistance between the embedded conductor wire and the brush body. There is also a brush having a molded-in conductor wire. With a conventional molding apparatus, however, the conductor wire is molded-in parallel to the direction of compression of the powdered material, so that the wire conductor is embedded in the brush side or brush face. This brush is not applicable to some structure of a brush-holder. 7

The object of this invention is to provide a brush having on its top surface a conductor wire molded-in perpendicular to the direction of compression of the brush, and a method and apparatus for automatically manufacturing the same.

According to this invention there is provided an electrical machine brush having a conductor wire whose one end is embedded in the top surface of the brush and is moldedin perpendicular to the direction of compression of the brush.

In another aspect of this invention there is provided a method for manufacturing an electrical machine brush having a conductor wire whose one end is embedded in the top surface of the brush and is molded-in perpendicular to the direction of compression of the brush comprising the steps of supplying a powdered material for the brush into a compression chamber while inserting into the compression chamber one end of the conductor wire continuously being let out, compressing together the powdered material and a conductor wire within the compression chamber in a direction perpendicular to the conductor wire, and cutting the conductor wire to a predetermined length while ejecting a compressed article from the compression chamber.

In a further aspect of this invention there is provided an apparatus for manufacturing an electrical machine brush having a conductor wire whose one end is embedded in the top surface of the brush and is molded-in perpendicular to the direction of compression of the brush comprising a base plate having a compression chamber for compressing a brush body, a feeder for feeding a powdered material into the compression chamber, a hopper for supplying the powdered material into the feeder. an upper die wall adapted to open and close an upper opening of the compression chamher and having the conductor wire inserted therethrough, a pair of reciprocable punches defining opposite side walls of the compression chamber and adapted to compress the powdered material and the conductor wire within the compression chamber, a cutter for cutting to a predetermined length the conductor wire whose one end is embedded in the brush body to be compressed by the pair of reciprocable punches, and an ejector set flush with the bottom surface of the compression chamber during compression and adapted to knock out a compressed article from the compression chamber upon completion of the compression.

The present invention can be more fully understood from the following detailed description when taken in connection with reference to the accompanying drawings, in which:

FIG. 1 is a front view, partly broken away, of an apparatus according to this invention;

FIG. 2 is a side view of the apparatus of FIG. 1;

FIG. 3 is a cross sectional view taken along lines III- -Ill of FIG. 2;

FIG. 4 is a schematic diagram showing parts or components in the neighborhood of a compression chamber of the apparatus of FIG. 1;

FIG. 5 is a plan view of a cutter of the apparatus of FIG. 1; and

FIG. 6 is a cross sectional view of the cutter of FIG. 5.

Referring to FIGS. 1 to 4 there is shown a base plate 1 having at its center a compression chamber or die cavity 2 for compressing a brush body. On the top surface of the base plate 1 is disposed a feeder 4 for feeding a powdered material a into the compression chamber 2. Mounted to the feeder 4 is a hopper 5 for feeding the powdered material thereto. A pair of reciprocable punches 6,6 for compressing the powdered material to a predetermined shape constitute opposite side walls of the compression chamber 2. The top surface of an ejector 7 is set flush with the bottom surface of the compression chamber during compression and moved to knock out a compressed article from the compression chamber upon completion of compression. Above the compression chamber an upper die wall 3 is mounted to the actuating rod 14a of an actuating means 14 which is supported by columns 13 secured to the base plate 1. The upper die wall 3 is moved up and down to open and close an upper opening of the compression chamber 2. Through the upper die wall 3 a conductor wire 9 extends whose one end is to be embedded in a brush body 8. In a position above the base plate l and opposite to the feeder 4 there is disposed a cutter 10 adapted to cut to a predetermined length the conductor wire whose one end is embedded in the brush body.

The compression chamber 2 is defined by a die block 11 disposed on the upper step of a stepped hole la provided in the base plate 1, the reciprocable punches 6,6 slidably movable in a groove 11a provided in the die block 11, the ejector 7, and the upper die wall 3. The die block I l is secured to the base plate 1 through a die block clamp I2.

Provided in the upper die wall 3 is a through bore 3a which meets at substantially a right angle to a conductor wire inserting bore 14!) provided in the side wall of the actuating rod 14a and extending halfway in its axial direction. The through bore permits one end of the conductor wire 9 whose the other end is wound around a delivery reel 15, to extend therethrough.

The feeder 4 assumes a rectangular-shaped box having an open bottom and a top inlet 4a through which the powdered material is charged. The feeder is reciprocably moved in a slidable fashion across the surface of the base plate 1 towards the compression chamber 2 by an actuating rod 16a of an actuating means 16. At the top surface of the feeder 4 is provided a shutter 17 for opening and closing the powder feeder mount 5a of the hooper 5. The punches 6,6 are respectively fixed to the end surfaces of actuating rods l8a,l 8a of actuating means 18,18 and are slidably moved towards each other so as to compress the powdered material together. The ejector 7 is fixed to an actuating rod 19a of an actuating means 19 mounted to the under surface of the base plate 1 and the actuating rod 19a extends up through the stepped hole In. The ejector is adapted to knock out the compressed article upwardly from the compression chamber.

The cutter for cutting the conductor wire 9 apart is constructed in a manner shown in detail in FIGS. 5 and 6. A lever 23 is swingably supported through a supporting shaft 21 whose lower end is screwed into a base block disposed on the base plate 1. The lever 23 has, at its free end, a fixed cutting edge 22a and a movable cutting edge 22b. An axially slidable lever 24 is attached, through elongated holes 36,36, to one side wall of the lever 23 by support screws 25,25, the elongated holes determining the scope of movement of the lever 24.

A pin 28 for engagement with an engaging slot 27 is provided on the top surface of the lever 24 at a predetermined distance from a pivotal axis 26 of the movable cutting edge 22b. On the under surface of the lever 24 is provided a pin 30 which is abutted against a stop 29 provided on the top surface of the base block 20 when the lever is swung. On the pivotal point i.e. a pivotal axis 21 of the lever 23 is mounted an auxiliary lever 31 which is at a predetermined angle to the axis of the lever 23. The free end of the auxiliary lever 31 is connectcd, as shown in FIG. 3, to one end of an actuating rod 32:: of a cutter cylinder 32.

On the base block 20 is provided a support 34 having an inner threaded hole through which an adjusting screw 33 is threadably inserted. The abutting of the end of the adjusting screw 33 against the side wall of the pin 30 regulates the counter-clockwise rotation of the lever 23. When the lever 23 is swung in the clockwise direction to cause the pin 30 to be abutted against the stop 29, the auxiliary lever 24 is slidably moved in a direction indicated by an arrow as shown in FIG. 5 and the movable cutting edge 22); is closed about the pivotal axis 26. During this portion of the period a conductor wire located between the fixed and movable cutting edges is cut apart.

Reference numerals 35 as shown in FIGS. 1 and 3 indicate detective sections of a control device (not shown) for controlling the scope in which the actuating rods 14a, 16a, 18a, 19a and 32a are actuated. The detection section 35 consists of an actuator 35a and a switch 35b.

Let us now explain the operation ofa brush manufacturing apparatus so constructed.

First of all each of the actuating rods 14a, 16a, l8a, 19a and 32a is withdrawn in a position as indicated in the figures. Then, the actuating rod 16a of the actuating means 16 is slidably moved to cause the powdered material a held within the feeder 4 to be fed within the compression chamber 2. At this time the mouth 5a of the hopper 5 is closed by the shutter 17. The feeder 4 is withdrawn to an original position and the powdered material held within the hopper is supplied through the mouth 5a of the hopper while the upper die wall 3 is moved down to close the compression chamber 2. At this time one end of the conductor wire extends from the bottom end of the upper die wall 3 into the compression chamber 2. Then, the pair of reciprocable punches 6,6 are slidably moved toward each other a predetermined distance to compress the powdered material to a brush body with the conductor wire 9 whose one end is embedded in the brush body. And then the upper die wall 3 and the punches 6,6 are retracted to the respective original positions. During this portion of the period, since the brush body is forced to adhere to the associated side walls of the die block 11, the conductor wire 9 is let out to a predetermined length. Thereafter, the actuating rod 32a of the cutter 10 extends a predetermined amount to permit the conductor wire 9 to be located between the fixed cutting edge 22a and the movable cutting edge 22b of the cutter, thereby cutting it to a predetermined length. Simultaneous with the withdrawal of the cutter 10, the ejector 7 is moved upward to permit an article A to be ejected from the compression chamber 2. At the same time the feeder 4 begins to be slidably moved and, when the ejector is retracted to an original position, feeds the powdered material to the compression chamber 2, while pushing the article A to a predetermined position by the front wall of the feeder 4.

Thus, compressed articles with the conductor wire are continuously obtained by repeating such operations. When the article is baked or sintered in a furnace (not shown), then a brush assembly is easily obtained.

It is needless to say that the number of conductor wires so embedded as well as the corresponding embedding positions can be optionally selected.

As will be understood from the above explanations, according to this invention electrical machine brushes with a conductor wire are very efficiently manufactured and this allows mass production of brushes.

Furthermore, it is possible according to this invention to obtain a brush with a conductor wire arranged in a direction perpendicular to a compressing direction. Since the conductor wire is firmly bonded within a compressed body by lateral pressures applied, an electrical resistance between the conductor wire and the brush body is maintained minimum and constant, thus saving a lot of cumbersome manual operations with the attendant advantage.

What is claimed is:

l. A method for manufacturing an electrical machine brush having a molded-in connector wire, said brush comprising a rectangular solid body, said body comprising a contacting face for contacting a moving element of an electrical circuit, a top face opposite said contacting face, and two opposed side faces having relatively large surface areas; the method comprising the steps of:

a. supplying a powdered material adapted to form the brush body into a compression chamber;

b. inserting into the compression chamber one end of the connector wire such that the connector wire is disposed through the top face of the brush when formed;

c. compressing the powdered material and the conneetor wire within the compression chamber by applying pressure to said side faces;

d. cutting the conductor wire to a predetermined length; and

e. ejecting the so formed brush from the compression 

1. A method for manufacturing an electrical machine brush having a molded-in connector wire, said brush comprising a rectangular solid body, said body comprising a contacting face for contacting a moving element of an electrical circuit, a top face opposite said contacting face, and two opposed side faces having relatively large surface areas; the method comprising the steps of: a. supplying a powdered material adapted to form the brush body into a compression chamber; b. inserting into the compression chamber one end of the connector wire such that the connector wire is disposed through the top face of the brush when formed; c. compressing the powdered material and the connector wire within the compression chamber by applying pressure to said side faces; d. cutting the conductor wire to a predetermined length; and e. ejecting the so formed brush from the compression chamber. 